Business data may be stored within relational database tables. The structures and inter-relationships of the database tables are complex. Business Intelligence (BI) tools therefore use an abstraction layer to shield end users from the complexity of the physical tables. The abstraction layer allows end users to query database tables using intuitive terms rather than requiring the end users to create query language statements which refer to specific entities of the database tables.
A developer may define “information models” intended to represent data needed for a particular business task. To increase system performance and reduce system complexity, a single user-generated query is typically limited to data contained in a single information model. Moreover, since information models are not joined to one another (also due to performance and complexity considerations), a query directed to data of multiple information models would return multiple independent result sets.